Phenmetrazine is a central nervous system stimulant currently used as an anorectic agent. The drug is abused and is reported to cause death from overdose. We describe a new derivatization method for phenmetrazine using 4-carbethoxy-hexafluorobutyryl chloride. Quantitation of urinary phenmetrazine can be easily achieved by using N-ethyl amphetamine as an internal standard. The electron ionization mass spectrum of 4-carbethoxyhexafluorobutyryl derivative of phenmetrazine showed a molecular ion at m/z 427 and a base peak at m/z 70. In the methane chemical ionization mass spectrum, the base peak was observed at m/z 428 (protonated molecular ion). In the electron ionization mass spectrum of 4-carbethoxyhexafluorobutyryl derivative of the internal standard, N-ethyl amphetamine we did not observe a molecular ion. However, in the chemical ionization mass spectrum, the protonated molecular ion at m/z 414 was the base peak. The retention time of derivatized phenmetrazine (8.4 min) was substantially longer than the retention time of the underivatized molecule. Moreover, underivatized phenmetrazine showed poor peak shape (substantial tailing) while derivatized phenmetrazine had excellent chromatographic properties. The within-run and between-run precisions of the assay were 2.6% and 3.1% respectively at a urinary phenmetrazine concentration of 10 µg/mL. The assay was linear for urinary phenmetrazine concentration of 1 to 100 µg/mL with a detection limit of 0.2 µg/mL.

Author Information:

Dasgupta, A Professor of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, Houston, TX

Hart, A Resident physician, medical laboratory technician, and supervisor of toxicology, University of New Mexico Health Sciences Center, Albuquerque, NM

is a member of CrossRef.
Author Title Gas Chromatography-Electron Ionization and Chemical Ionization Mass Spectrometric Analysis of Urinary Phenmetrazine After Derivatization with 4-Carbethoxyhexafluorobutyryl Chloride—A New DerivativeSymposium , 0000-00-00Committee E30